(a) Field of the Invention
The present invention relates to a backlight assembly having an improved heat releasing structure and a display device having the backlight assembly, and more particularly to a backlight assembly that can efficiently release the heat generated from lamp electrodes to an area external to the assembly and a display device having the backlight assembly.
(b) Description of the Related Art
Due to the recent drastic development of semiconductor technologies, the demand for display devices of a small size, light weight, and improved performance has explosively increased.
Liquid crystal display (LCD) devices, which employ an LCD panel, have been recently spotlighted for providing advantages such as small size, light weight, and low power consumption and have been regarded as a substitute for cathode ray tubes (CRTs). Now, the LCD devices are widely used in information processing apparatuses requiring a display device.
The LCD devices change a specific molecular alignment of liquid crystals with application of voltage. The LCD devices convert the change in optical characteristics such as birefringence, optical rotary power, dichroism, and optical scattering of liquid crystal cells emitting light that result from the change in molecular alignment into visual change. Thus, the LCD devices display data by using modulation of light in the liquid crystal cells.
Since the LCD device is a light-receiving display device that does not emit light by itself, a backlight assembly supplying light to the LCD panel is often provided below the LCD panel. The backlight assembly includes a lamp, a diffusing plate, a reflecting plate, and optical sheets. For the lamp, a cold cathode fluorescent lamp (CCFL) is usually used. CCFL has a small amount of heat emission, generates white light close to natural light, and has a long life.
The heat generated from the lamp is delivered to the reflecting plate adjacent to the lamp by means of radiation, and is released through a bottom chassis contacting the reflecting plate. With an increase in display size driven by user preference, the conventional display devices usually include a plurality of lamps to form an image with sufficient brightness. A large amount of thermal energy is generated from the backlight assemblies of large display devices because of the increase in the number of lamps.
A disadvantage of the conventional bottom chassis structure is its limited ability for releasing the thermal energy. Accordingly, the thermal energy cannot be readily released, thereby increasing the device temperature. As a result, the fluorescent material of the lamps is deteriorated and the life of the lamps is reduced. In addition, the reflecting plate is deteriorated, adversely affecting the performance of the reflecting plate, and the lamp holder is deformed due to the thermal energy generated from the lamp. The vaporization pressure of mercury in the lamps is also affected so that the brightness is reduced with the increase in the number of lamps.
Specifically, in large LCD televisions incorporating a long lamp, current leakage and temperature difference occur between the electrodes. In this case, the temperature of a hot electrode is higher than that of a cold electrode used as a ground electrode. Specifically, in LCD televisions, the temperature of the hot electrode increases more rapidly when turning on the power than when turning off the power. This is because the heat generated from the hot electrode is not released but stays in the vicinity of the hot electrode. The temperature difference reduces the life of the lamps.
A method of directing the heat to prevent these adverse effects of temperature increase in the device is desired.